Senna preparations and methods of making and using them



Jan. 16, 1968 c. A. FRIEDMANN E A SENNA PREPARATIONS AND METHODS OFMAKING AND USING THEM 2 Sheets-Sheet 1 Filed Jan. 21, 1966 ,1968C.A.FRIEDMANN ET AL 3,364,113

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United States Patent 3,364,113 SENNA PREPARATIONS AND METHODS OF MAKINGAND USING THEM Charles Aubrey Friedmann, Church Row, London, and HerbertAlan Ryan, Bedford Park, London, England, assignors to WestminsterLaboratories Limited, London, England, a corporation of the UnitedKingdom Coutinuation-in-part oi application Ser. No. 189,286, Apr. 23,1962, which is a continuation-impart of application Ser. No. 760,534,Sept. 12, 1958. This application Jan. 21, 1966, Ser. No. 522,098

16 Claims. (Cl. 167-56) This invention relates to new and novelderivatives of senna which are useful therapeutically. In particular, itrelates to1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-10,10'-dihydrodianthrone,its pharmaceutically acceptable basic salts, compositions containingthese compounds, methods for their preparation and the methods forachieving a pharmacologic effect of peristaltic stimulation.

This application is a continuation-in-part of our copending application,Ser. No. 189,286, filed Apr. 23, 1962, which in turn was acontinuation-in-part of applicants then co-pending application, Ser. No.760,534, filed Sept. 12, 1958, now abandoned.

It has been customary for many years to prepare extracts of senna byextracting the drug with water, using either the aqueous infusion or themore concentrated liquid extract obtained by evaporating aqueousmacerates. More recently, Stoll et al., Helv. Chim. Act., 1949, 32:1892, were able to isolate from senna two active principles, sennosidesA and B, which methods have also been described in Us. Patent No.2,350,295.

With the development in recent years of a chemical method of assay forsennosides in senna by Fairbairn & Michaels, J. Pharm. Pharmacol., 1950,2:807, 813, it was discovered-that a considerable proportion ofsennoside's were lost when aqueous extracts were prepared. Later,Fairbairn & Saleh, J. Pharm. Pharmacol, 1951, 3:918, were able to show,by using a biological method of assay, that the crude drug was much moreactive than could be anticipated from its sennosides content asdetermined by chemical assay, the latter, which are rhein glycosides,accounting for about 60 percent of the total biologic activity of thedrug. These authors also showed that a small proportion of non-rheinglycosides of the anthraquinone group was present, but that some 30percent of the biologic activity remained unaccounted for.

As a result of these observations and our own experimental work, itbecame apparent that senna extracts of commerce sutfer from thefollowing defects:

1. A very substantial loss of the active glycosides originally presentin the senna.

2. Their biologic activity is equivalent only to their sennosidescontent, the extra associated activity present in the senna being lost.

The object of the present invention is to extract a substance possessingnot only the sennosides activity but also the extra associated activity,to concentrate it into highly active water-soluble forms, and to recovernew active extract of senna primary glycosides as well as extracts ofvarying degrees of activity but all more active than any products fromsenna heretofore known in the art.

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According to the invention the objects are achieved by a processcomprising the steps of extracting the senna with a neutral aqueousorganic solvent, or an aqueous organic solvent to which an organic acidhas been added but in character and amount that will not debase theprimary glycoside, and adding to the separated macerate a metal salt,preferably an alkaline earth metal, salt, e.g., sodium carbonate,potassium bicarbonate, magnesium carbonate, calcium acetate, magnesiumacetate and sodium citrate and an anhydrous organic solvent to causeprecipitation of a water-soluble product comprising the activeprinciples of the senna as a salt of the precipitating metal ion. Thewater-soluble salt thus obtained comprises the respective basic metalsalt of1,1'dihydroXy-3,3'-dicarboxy-8,8-digentiobiosyloxy-IO,10'-dihydro-dianthrone.Thus, for example, if calcium acetate is used as the precipitating metalsalt, the calcium salt of 1,1'-dihydroxy-3,3'-dicarboxy-8,8'digentiobiosyloxy-IO,10'-dihydrodianthrone will be obtained in intimateassociation with other active principles of the senna and if sodiumcarbonate, potassium bicarbonate or magnesium carbonate is used as theprecipitating salt, then the respective sodium, potassium or magnesiumsalt of1,l-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-IO,10'-dihydrodianthrone,will be obtained. The process will normally comprise further steps asdescribed hereafter but it should be mentioned that the aforesaidWatersoluble product is useful as such in the dry form or in solution,and since it possesses a hi h concentration of the active principles ofsenna, it is suitable for administration and may be incorporated in anyof the usual medicinal forms such as, for example, powders, compressedor molded tablets or pills, capsules, cachets, chocolate, chewing gum,pastilles, lozenges, granules, suppositories, enemas, syrups, elixirs,or injections, either alone or with other therapeutic agents.

One of the products thus obtainable is a stable non-hygroscopic powderwhich comprises the aforesaid respective basic metal salt, as forexample, calcium 1,1-dihydroxy- 3,3-dicarboxy 8,8digentiobiosyloxy-10,10-dihydrodianthrone and which may be stored forlong periods without deterioration. It contains 25 to 35 percent ofrhein glycosides by chemical assay and possesses an activity whendetermined by biological assay about 40 percent greater than could beexpected from the rhein glycosides as determined by the chemical assay.

The said further steps in the process comprise dissolving the aforesaidwater-soluble product in water and treating the solution with an agentserving to free it from metal ions. The treatment may be the addition ofan organic acid to produce and precipitate a water-insoluble salt of themetal, and removing the precipitate so as to recover a solution of theactive principles. Alternatively, the treatment is effected with anion-exchange resin whereby there is obtained a solution of the activeprinciples free from metal ions.

In either case, the resulting solution, preferably after evaporationunder reduced pressure at a temperature not exceeding 30 C. in order toremove a substantial amount of water, is caused to precipitate theactive principles as a water-soluble solid, by mixing with an anhydroussolvent such as isopropanol. The resultant compound,l,1'-dihydroxy-3,3-dicarboxy 8,8digentiobiosyloxy-lll,10-dihydrodianthrone, is obtained in substantiallypure form as a result of this treatment.

The portion of the senna used may be the entire plant, the leaf, and/ orthe pod (with or without seed) preferably in powder form. The processmay be performed as follows:

The first stage is to extract the active principles of the senna,preferably completely with either (a) a pH neutral aqueous organicsolvent, preferably 70 percent ethanol, 70 percent acetone or 70 percentisopropanol, using desirably a v./w. ratio of approximately 16:1 solventto senna or, (b) the same aqueous solvent together with an organic acidwhereby the v./w. ratio of solvent to senna is reduced to approximately7:1. The separated macerate is treated with calcium acetate andanhydrous solvent, e.g., ethanol, acetone or isopropanol, in each caseusing one to three volumes of anhydrous solvent to one of macerate. Aprecipitate of a product consisting of the active principles togetherwith calcium is formed, which is filtered off, the resulting filtercake, containing the greater part of the activity of the senna, beingdried at atmospheric temperature under conditions of low humidity. Theproduct obtained as a result of this step is the calcium salt of1,1-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-lO,l-dihydrodianthrone together with other precipitated sennaprinciples. It is the calcium 1,1-dihydroxy3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,10'-dihydrodianthrone which isthe portion containing the greater part of the activity of theprecipitate.

It will be appreciated that the proportions of the materials used may bevaried over substantial ranges. For instance, the concentration of theaqueous extracting solvent, although preferred as about 70 percent, maybe desirably within the range of about 50 percent to about 80 percent.The most desirable solvents are substantially pH neutral aqueous organicsolvents which solvents do not substantially change the activity of theprinciples being extracted. Exemplifying such solvents there may bementioned liquid alkanols of from 1 through 3 carbons, such as methanol,ethanol, propanol, isopropanol, acetone, dioxane, and mixtures thereof.Higher alcohols like butyl and amyl are not as useful since mostdesirably the alcohols should be substantially completely miscible withwater in practically all proportions.

If an organic acid is added to the solvent, the amount is preferablyabout 2 percent based on the weight of the senna, but desirably it maybe within the range of about 1 percent to about 6 percent, and evenhigher. The solvent or solvent and acid combination should not effectthe primary glycoside to any undesirable degree. The acid, for example,may be monobasic, dibasic and tribasic, water-soluble aliphatic acids,illustrated by lower acids of the acetic series such as acetic,propionic, butyric and polybasic acids such as tartaric, succinic,maleic, and citric, and mixtures thereof. When an acid is. present thev./w. ratio of solvent to senna may be within the range of about :1 toabout 15:1, but when an acid is not present the ratio may be within therange of about :1 to about 30:1.

The metal salts added to the separated macerate may be, desirably,alkaline earth metal salts, such as calcium, magnesium, sodium,potassium and lithium. These metal salts are desirably salts of organicacids, as enumerated above. However, the carbonate and bicarbonate saltsmay also be utilized. The amount of metal salt, as for example, calciumacetate, which is added, is preferablywithin the range of about 2percent to about 10 percent, based on the weight of the senna. Theamounts of the selected metal salts to be added to form the respectivemetal salt of 1,1 dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,10-dihydrodianthrone, is preferably within the range of from about 2percent to about 10 percent, based upon the weight of the senna. Thepresence of an excess of the metallic ion is not critical and therespective metallic salt of the1,1-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy-10,10-dihydrodianthrone,will be obtained in good yield when these concentrations are used. Thus,if the calcium, magnesium, sodium, potassium and lithium. ions are usedto form the metallic salt, then the calcium 1,1'-dihydroxy 3,3dicarboxy-8,8-digentiobiosyloxy-10,l0-dihydrodianthrone; magnesium1,1'-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,l0'-dihydrodianthrone; sodium 1,1dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-10, 10-dihydrodianthrone;potassium 1,1'-dihydroxy-3,3'-dicarboxy8,8-digentiobiosyloxy-10,l0'-dihydrodianthrone or the lithiuml,l-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-lO,10-dihydrodianthroneis the metallic salt obtained. The dry metallic salt, together withprecipitate of other principles of senna, which are obtained as a resultof the above steps, may be utilized for further processing, although theresulting compositions obtained from the aforesaid procedure may beutilized directly in therapy.

The dried product which contains the appropriate salt of 1,1dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,l0-dihydrodianthrone, together with precipitated senna principles,which is obtained as a result of the above steps, is dissolved in waterand treated with an appropriate organic acid in order to renderinsoluble the metallic ion present. Thus, when calcium is the metallicion which is present, then oxalic acid may be used, as the precipitatingacid. Such other acids which may be used to precipitate the respectivemetal ion include suitable inorganic acids, as for example, sulfuricacid, to form the insoluble calcium sulfate. In some instances, as forexample, when the sodium, potassium, and lithium ions are used, then theacid may liberate the metal ion in a soluble form and require an organicsolvent to precipitate it, as for example, the addition of acetone.

Alternatively, the solution of the water-soluble metallic salt obtainedas described above, may be treated with a strongly acid ion exchangeresin such as Zeo-Karb 225 (H Form. The active principles, in eithercase, remain in solution and are precipitated from the filtrate(concentrated under reduced pressure, below 30 if necessary), by theaddition of about four volumes of anhydrous solvent, e.g., ethanol,acetone, isopropanol or any of. the other organic solvents alone or inadmixture as set forth above. The precipitate is collected and dried atroom temperature at low humidity.

The resulting dry powder is soluble in water and is a highly activestable concentrate containingthe substantially pure 1,1dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-10,10-dihydrodianthrone.When deseeded pod is utilized as a starting material, an activity indexof 40 to 50 percent of rhein glycosides by chemical assay may be shownbut which possesses an activity when determined by biological assay ofabout 40 percent greater than could be expected from the rheinglycosides as determined by the chemical assay.

Similar results are obtained both from pod with seed and from leaf, butthe proportions of active substance in the final concentrates are lower.For example, the concentrate from pod with seed contained 30 to 40percent of rhein glycosides by chemical assay, and that from leaf 25 to35 percent, although each possesses an activity when etermined bybiological assay about 40 percent greater than its chemical assayresult, exactly as in the case of the concentrate obtained from podwithout seeds. 7

This highly active extract may be employed both in the dry form and insolution, and is suitable for administration in any of the usualmedicinal forms such as those aforementioned.

The invention is based on the fact that the main active principle ofsenna is extracted as a primary glycoside, that is, a water-solubleprimary anthracene glycoside. This primary glycoside exerts a desirablephysiologic eflect by stimulating peristalsis and may be obtained as theprincipal active agent of an especially prepared concentrate obtainedfrom the senna plant or portions thereof, as well as in the pure form.This active principle has a different chemical composition from theactive crystalline glycoside in glacial acetic acid or whencatalytically hydrogenated over a palladium-charcoal catalyst affordstwo molecules of gentiobiose and one molecule of sennidine. Sennosidesunder these conditions give two molecules of glucose and one molecule ofsennidine.

TABLE A.CO1\PARISON OF PROPERTIES sennoside, U.S. Pat. Subject 2, 5Glycoside 1. Biological Activity (by bioassay) 100 145. 2. Chemical (a)C content 52.5% H content 4.9%. (b) Aglycone content 45.5% (c) Glucosecontent 57.6% ((1) Equivalent weight 4 600. (e) Acetyl conent ofpurified acetyl derivative. Equiv. weight of acetyl derivative 960. (f)Action of 0.1 N acid Givcelzs senno- S1 es. (g) Consumption of K10 permol 4 mol 8 mol. (h) Result of reduction with sodium di- Product solublein ether Product inthionite. soluble in ether. 3. Physical:

(a) Color Bright yellow Buff yellow. (1)) Solubility in cold Waten.Traces Very soluble (1 pt. in parts). (0) Molecular weight (Isopiesticmethod)--. 862 1,165. (d) Paper chromatography R; values (by O 1.0.

ascending technique) using Whatmans N0. 1 paper.

(e) Melting point 200-240 C ISO-186 C 1575160; C.

ec. (f) Specific Rotation M 160 100 0. (g) Absorption spectra:

A max. (12 m 210 270 265.

cm. E km. my 235 220 218. Note: These values are not altered byrecrystallizing the materials twice from ethyl Cellosolve and once fromdimethyl-formamide with isopropyl alcohol. (h) Molecular Extinction20,270 19,750 25,800.

the properties of the active principle obtained as a result of the stepsdescribed in the present application with the known glycosides obtainedas a result of practicing the teachings of U.S. Patent 2,350,295,clearly establishes the different nature, physical and chemicalproperties of the subject compound from those principles which werepreviously known. This comparison is presented in Tables A and B. Thenew subject active principle, which is termed senna primary glycoside isshown to have the following different chemical, physical and biologicalproperties from those of the known sennosides (U.S. Patent 2,350,295).

1. The subject senna primary glycoside is very soluble in water; it is aglucose glucosyl glycoside (1,1-dihydroxy- 3,3 dicarboxy 8,8digentiobiosyloxy 10,10 dihydrodianthrone) having the graphic formulashown in FIGURE 1. The structure of the glycone (i.e., the glucoseglucosyl moiety) is that of gentiobiose which is a disaccharide.

2. Sennoside (U.S. Patent 2,350,295) which is almost insoluble in water,is a secondary glucoside (8,8'-diglucosyl-IO,l0'-dihydrorheindianthrone)and has the graphic formula shown in FIGURE 2. The structure of theglucose is that of glucose, which is a monosaccharide.

3. Senna primary glycoside loses two molecules of glucose and iscompletely degraded into sennoside (U.S. Patent 2,350,295) by treatmentwith mineral acid in aqueous solution, the sennoside graduallyprecipitating as an insoluble crystalline powder. By this procedure, 1gram of senna primary glycoside yields 0.72 gram of sennoside.

4. Alternatively, senna primary glycoside on being boiled in methanol,with or without the addition of small quantities of oxalic or citricacid, deposits crystals of sennoside. Alternatively, senna primaryglycoside when boiled TABLE B.PAPER CHROMATO GRAPHIC COMPARISONS A AND BWITH THE SUBJECT PRIMARY *U.S. Patent No. 2,350,295.

5. Biological activity. 1 gram of senna primary glycoside, although itcontains in chemical combination only the equivalent of 0.72 gram ofsennoside, has nevertheless the biological activity of 1 gram ofsennoside obtained as a result of U.S. Patent No. 2,350,295.

The senna glycoside (obtained through applicants process) is a primaryglycoside and is very soluble in water; it is a glucose glucosylglycoside (l,l-dihydroXy-3,3-dicarboXy-8, 8-digentiobiosyloXy-10,l0'-dihydrodianthrone) having the graphic formula shown in FIGURE 1. Thestructure of the glycone (i.e., the glucose glucosyl moiety) is that ofgentiobiose, which is a disaccharide.

Sennoside (U.S. Patent No. 2,350,295), which is almost insoluble inwater, is a secondary glycoside (8,8- diglucosyl 10,10dihydrorheindianthrone) and has the graphic formula shown in FIGURE 2.The structure of 7 the glycone-is that of glucose which is amonosaccharide. The compound l,l'-dihydroxy-3,3' dicarboxy 8,8digentiobiosyloxy-lO,10'-dihydrodianthrone is obtained in the pure formfrom the concentrate prepared as described above, as Well as directlyfrom the senna plant. The procedures consist of extracting the sennaplant with an aqueous organic solvent in which the active principles aresoluble but in which the inactive matter is not. A suitable aqueousorganic solvent for this purpose is from 70 to 85 percent alcohol and 85percent isopropanol is preferred. The extract obtained in this way maybe further treated in order to obtain the desired compound in a highlypure form. The concentrates previously described may also be utilized inthis further treatment to obtain the pure compounds.

Essentially the steps involved are as follows: The product, which mayeither be the extract of the senna plant or the concentrates containingthe active principle, prepared as described above, are dissolved in anaqueous organic solvent, as for example, 85 percent isopropanol, or

any other suitable aqueous organic solvent, in which the activeprinciples are soluble, but in which some of the inactive matter isinsoluble. The solution is'filtered and the filtrate evaporated underreduced pressure at a'ternperature not exceeding 30 C. The evaporate isthen precipitated with an organic solvent such as anhydrous isopropanol,and the precipitate is then dissolved in an aqueous organic solvent,e.g., 85 percent isopropanol. The solution is passed through a cellulosecolumn or celitecharcoal column and the eluate is thenconcentrated andprecipitated with an anhydrous organic solvent such as isopropanol. Theprecipitate may then be dissolved by warming in an aqueous organicsolvent at relatively high concentration, e.g., 90 percent isopropanol,and the solution allowed to crystallize. The crystals may then beseparated and dried, preferably under reduced pressure and atatmospheric temperature.

The product,1,1'-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-l0,10-dihydrodianthrone,is a buff yellow crystalline powder, very soluble in cold water whichdiflers markedly from sennosides A and B. It has a melting point of 157to 159 C. (with decomposition), a molecular weight of 1164 as determinedby the isopiestic method, and an equivalent weight of about 615 whendetermined by potentiometric titration. Sennosides are almost insolublein cold water; they have a molecular weight of 862,

I an equivalent weight of 461 and melting points of, for A,

210240 C. (with decomposition), and, for B, 180- 186 C. (withdecomposition). The new substance is an active glycoside, based onrhein, in a pure state of purity, and contains the equivalent of 73percent of sennosides by chemical assay, whereas its activity bybiological assay is equivalent to a content of 100 to 110 percent ofsennosides. It is stable when stored in well closed containers and issuitable for administration in any of the usual medicinal forms.

The compound,1,l'-dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-lO,1'-dihydrodianthrone,may be reacted with alkali metal basic salts, as for example, sodium,po-

tassium, lithium, magnesium and calcium, carbonate, bi-

cabonates or hydroxides, toform the corresponding alkali 0 C8 3'dicarboxy-S,8'-digentiobiosyloxy-10,10-dihydrodian= throne.

The present invention enables the achievement of a de (i.e., through theoral or rectal routes), of the productsof the present invention, eithercombined with a pharmaceutically acceptable vehicle or used alone.Preferably, the 1,1 dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-l0,10'-dihydrodianthrone will be administered rather than a compositioncontaining the same, although from the viewpoint of desired physiologiceffect, the same qualitative pharmacologic actions will result.

Desirably, the biologically active dosage forms will contain a range inconcentration of active ingredient of from 1 mg. to mg. of the new rheinglycosides, as determined by chemical and biologic assay, per unit dose.The total daily dose to be administered to humans and animals, willusually be within the range of from 1 mg. to 40 mg. of the activecompound. The specific total daily dose will depend upon the therapeuticgoal and the particular status of the patient. Thus, if a strongpurgative etiect is desired, the upper range in dosage will be utilized,whereas if a milder laxative effect is intended, then the lower dosagerange will be administered. Similarly, an infant, a geriatric patientand a debilitated patient, will require less of the new compound thanwill a patient who has an occasional episode of constipation. Theindividual (human or'animal) having certain pathologic disorders of thegastrointestinal tract, may also requireappropriate adjustment indosage. Thus, the patient with Hirschsprungs disease, will require alarger dose of the new compound than will a patient who has a spastictype of constipation.

The particular dosage forms to be used in the administration of thesenew compounds include tablets, granules, powders, capsules, solutions,and suppositories. In preparing these individual dosage forms, eitherthe 1,1-dihydroxy 3,3dicar-boxy-8,8-digentiobiosyloxy-10,l0'-dihydrodianthrone, or apreparation containing 1,1-dihydroxy3,3'-dicarboxy-8,8-digentiobiosyloxy10,l0-dihydrodianthrone or theappropriate metallic salts of 1,1- dihydroxy3,3'-dicarboxy-8,8-digentiobiosyl0xy-10,10? dihydrodianthrone, may beutilized, adjusting the particular concentration to be within the rangeof from 1 mg. to 40 mg. per unit dose, based upon the quantity of 1,1-dihydroxy 3,3'-dicarboxy-8,8'-digentiobiosy1oxy-10,10-dihydrodianthrone, as determined by chemical and biologic assay.

The following examples illustrate the scope of this invention.

I EXAMPLE 1 One kilogram'of powdered s'enna pod, freed from seeds,

is mixed with 6 liters of 70 percent ethanol containing 20 g. citricacid, stirred for a period of six hours, and then set aside for 15hours. The mixture is filtered under slightly reduced pressure, the marcbeing mixed with a further liter of 70 percent ethanol and againfiltered. The combined filtrates, about 6.5 liters, are mixed with g. ofanhydrous calcium acetate which is added slowly, and after a few minutesa bufi colored precipitate separates.

Stirring is continued for about ten minutes, 6.5 liters of anhydrousethanol are added, and the precipitate collected glycosides'by chemicalassay, its total activity determined by biologic assay being equivalentto. 35 to percent of sennosides.

EXAMPLE 2 In place of the calcium acetate used 'asdescri-bed in 7Example 1 above, there may be substituted any pharmasolution as an enemaand in this event, the unit dose may be as large as 1 quart, and as lowas 4 ounces. However, the concentration of active ingredient per unitdose does not change, i.e., from 1 to 40 mg. of active ingredient perunit dose.

When a solid dosage form is desired, as for example, capsules, tablets,powders, granules or suppositories, then these may be prepared bycombining either 1,1-dihydroxy- 3,3'-dicarboxy-8,8-digentiobiosyloxy10,10 dihydrodianthrone, its basic metallic salts or a preparationcontaining the same, with a pharmaceutically acceptable carrier, andthis is then manufactured into the appropriate dosage forms. In thepreparation of tablets, a diluent such as starch, lactose or sucrose maybe used, in proportions of from 10 to 90 percent of the concentration ofthe active substance utilized. To this mixture is added apharmaceutically acceptable binding agent, such as gum acacia,tragacanth, or polyvinyl pyrrolidone and a pharmaceutically acceptablelubricant such as magnesium stearate. After granulating the mixture, thetablets are compressed into suitable size and shape, each tabletcontaining from 1 mg. to 40 mg. of the active substances.

Capsules may be prepared by filling a suitable gelatin capsule witheither1,ldihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,l-dihydrodianthrone,the metal salts of 1,1 dihydroxy 3,3-dicarboxy-8,8'-digentiobiosyloxy-10,10-dihydrodianthrone or compositions containing the same. It may bepreferred to mix the active substance with a suitable diluent prior tothe filling of the capsule and such diluents as starch, lactose andsucrose may be used. Granules and tablets are prepared by eithergranulating the tablet formulation prior to compression into tablets orby mixing the selected active substance with a granulating vehicle, asfor example:

Parts Mannitol 80 Sucrose 15 Magnesium stearate 5 The proportion of thegranulating vehicle to the active ingredient is from to 90 parts ofgranulating vehicle to from 90 to 10 parts of active substance. Afterintimately mixing the two components, the mixture is moistened withwater or alcohol or mixtures of these, and passed through a screenhaving a porosity, or mesh size, of not smaller than No. 8 US. standardmesh. The resultant granules are then air dried. The amount of granulesto be administered per unit dose will depend upon the concentration ofactive ingredient per gram of granules, to result in a range of from 1to mg. per unit dose. Powders may be prepared by using the sameformulation as is used for the granules but reducing the particle sizeto below a No. 60 standard mesh size.

When a suppository is desired, then an appropriate quantity of thedesired active ingredient is mixed with a pharmaceutically acceptablesuppository base, such as cocoa butter, carbowax, cetyl alcohol andmixtures of these and the Whole molded into suppositories of about 2 gm.in weight. The range in concentration of active ingredient persuppository is from 1 to 40 mg. of active ingredient.

What is claimed is:

1. A compound selected from the group consisting of 1,1dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10, 10-dihydrodianthroneand its pharmaceutically acceptable metal salts.

2. 1,1-dihydroxy 3,3 dicarboxy-S,8-digentiobiosyl oxy-10,10'-dihydrodianthrone.

3. The calcium salt of 1,l-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-l0,10'-dihydrodianthrone.

4. The sodium salt of 1,1-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,10-dihydrodianthrone.

5. The potassium salt of 1,1-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy-l 0,1 0-dihydrodianthrone.

6. The lithium salt of 1,1'-dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-l0,l0'-dihydrodianthrone.

7. The magnesium salt of1,1-dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-10,10-dihydrodianthrone.

8. The process of preparing1,1-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy 10,10dihydrodianthrone which comprises the steps of:

(a) adding to a vegetable substance containing 1,1-

dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy 10, 10-dihydrodianthroneselected from the group consisting of senna, an extract of senna, sennapod and deseeded senna pod, a substantially pH neutral aqueous organicsolvent, said solvent containing from 20 to 50 percent of water and saidorganic solvent selected from the group consisting of methanol, ethanol,propanol, isopropanol, acetone, dioxane, and mixtures of these, or anaqueous organic solvent containing from 20 to 50 percent of water, saidorganic solvent being selected from the group consisting of methanol,ethanol, propanol, isopropanol, acetone, dioxane and mixtures of theseand from 1 to 6 percent by weight of an organic acid, soluble in saidaqueous organic solvent,

(b) separating any insoluble material from the resulting liquid extract,and

(c) adding to said liquid extract an ionizable metal compound selectedfrom the group of metals consisting of sodium, potassium, lithium,magnesium, and calcium, and

((1) adding an anhydrous form of said organic solvent to precipitate afirst Water-soluble product containing1,1-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy-10,l0'-dihydrodianthrone, in the form of the salt of said metal moietyadded,

(e) isolating said precipitated first water-soluble product containingsaid metal salt of 1,1-dihydroxy-3,3- dicarboxy-8,8'-digentiobiosyloxy10,10 dihydrodianthrone,

(f) dissolving said first water-soluble product in water,

(g) treating the resultant aqueous solution with an agent selected fromthe group consisting of cationic ion exchange resin and acid ions whichprecipitate the metal moiety present in the form of said salt of1,1'-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosy1-oxy-IO,10-dihydrodianthrone, filtering, evaporating to low volume andadding an anhydrous form of said organic solvent to precipitate a secondwater-soluble product,

(h) redis'solving said second water-soluble product in said aqueousorganic solvent, passing the resultant solution through an adsorbingcolumn, concentrating the eluate and isolating1,1'-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy 10,10dihydrodianthrone therefrom.

9. The method of preparation of a laxative compound containing the metalsalt of 1,1'-dihydroxy-3,3-dicarboxy- 8,8digentiobiosyloxy-IO,10'-dihydrodianthrone, which comprises the stepsof:

(a) adding to a vegetable substance containing 1,1-dihydroxy-3,3'-dicarboxy 8,8 digentiobiosyloxy- 10,10-dihydrodianthroneselected from the group consisting of senna, senna pod, an extract ofsenna and deseeded senna pod, a pH neutral aqueous organic solventcontaining from 20 to 50 percent by weight, of water, and an organicsolvent selected from the group consisting of ethanol, methanol,isopropanol, acetone, dioxane and mixtures of these, or an aqueousorganic solvent containing from 20 to 50 percent by weight, of water andan organic solvent selected from the group consisting of methanol,ethanol, propanol, isopropanol, acetone, dioxane and mixtures of theseand at least 1 percent of an organic acid,

(b) separating any insoluble material from the resultant liquid mixture,and

(c) adding to said filtered liquid an ionizable metal compound in whichsaid metal moiety is selected ceutically acceptable metal salt which issoluble in the solvent system used. When such metal ions as sodium,potassium and lithium are utilized, it may be necessary to fractionallyprecipitate the final product by concentrating the solvent under reducedpressure. The resultant precipitate is dried and contains theappropriate metal salt of 1,1dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-10,l'-dihydrodianthrone. Under certain conditions it may be desirable toutilize the carbonate, bicarbonate or hydroxide of the metal ion, eventhough it may be insoluble in the particular solvent system utilized.When these insoluble metallic salts are used, then these must be finelysubdivided and added to the reaction mixture while stirring for asufiicient period of time to insure complete reaction. Theneutralization and change in pH will afiord a reliable index as to thecourse of the reaction. It is important to note that careful pH controlis necessary in order to avoid hydrolytic cleavage of the primaryglycoside.

EXAMPLE 3 The 'dry precipitate, which contains the calcium salt of1,1-dihydroxy-3,3'-dicarboxy 8,8'- digentiobiosyloxy-IO,10-dihydrodianthrone, prepared according to Example 1, is dissolved in220 ml. of water, the resulting solution being mixed with 20 gm. ofpowdered oxalic acid, stirring EXAMPLE 4 The dry precipitate, preparedaccording to Example 1, is dissolved in 1600 ml. of water, 200 gm. of astrongly .acid ion exchange resin, such as the commercial brand known asZeo-Karb 225 (H Form) are added and the mixture well stirred until thesolution no longer contains calcium ions. The solution is filtered andthe filtrate evaporated to 250-300 ml. under reduced pressure and at atemperature not exceeding 30 C. After removal of small quantities ofinsoluble matter by filtration, the brown solution is poured into 1.2liters of isopropanol with constant stirring. The resulting brownprecipitate of highly active concentrate is collected, washed 'with 200ml. of ethanol and dried in a low humidity chamber at atmospherictemperature; it weighs 50 to 60 gm. and contains 40 to 50 percent ofrhein glycosides by chemical assay, its total activity determined bybiological assay being equivalent to 55 to 70 percent of sennosides.This precipitate contains1,1'-dihydroxy-3,3-dicarboxy-8,8-diger1tiobiosyloxy-l0,10'-dihydrodianthrone.

EXAMPLE 5 One kilogram of powdered senna pod is mixed with 12 liters ofcold neutral 70 percent ethanol for 8 hours. After filtration the cakeis washed with a further 4 liters of the same solvent. The combinedfiltrates are stirred with 40 gm. of anhydrous calcium acetate for about15 minutes. Seventeen liters of acetone are added, and the precipitatecollected and dried at atmospheric temperature under reduced pressure.The dry product, about 100 to 150 -gm., is powdered and dissolved in 1.5to 2 liters of water, and stirred with about 200 to 300 gm. of Zeo-Karb225 (H form), until the solution is free from calcium ions. The solutionis filtered and the filtrate evaporated below 30 Counder reducedpressure to about 200 ml. One liter of isopropanol is added and theresulting yellowish brown precipitate collected and dried over P 0 atroom temperature. The product is substantially the same as that producedaccording to Example 3 and contains 1,1-dihydroxy-3,3-dicarboxy 8,8-digentiobiosyloxy-10,10-dillydrodianth'rone. 7

EXAMPLE 6 V the solution passed through a column containing about 150gm. of powdered cellulose. The column is then washed with 85 percentisopropanol until the eluate is almost colorless, and the total eluateevaporated to a syrup under reduced pressure at below 30 C. About 150ml. of isopropanol is added and the resulting yellowish precipitateseparated by filtration. The filter cake obtained in this way isdissolved in about 100 ml. of 90 percent isopropanol by warming and thesolution allowed to crystallize. The crystals are then separated anddried in vacuo at atmospheric temperature. About 4 gm. of V the activeprinciple in the form of a butt yellow crystalline powder is obtained.

EXAMPLE 7 To 0.02 mol of1,l'-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy 10,10dihydrodianthrone, dissolved in 100 cc. of water, is added 0.04 mol ofsodium bicarbonate. When the reaction is complete, 600 ml. of ananhydrous alcohol, such as isopropanol is added to precipitate thesodium salt of1,1'-dihydroxy-3,3'-dicarboxy-8,8-digentiobiosyloxy-10,l0'-dihydrodianthrone,which is filtered' and dried.

a EXAMPLE 8 In place of the sodium bicarbonate used in Example 7 above,there may be substituted in equivalent amounts,

sodium hydroxide, sodium carbonate, potassium hydroxide, potassiumcarbonate, potassium bicarbonate, lithium carbonate, lithiumbicarbonate, lithium hydroxide, magnesium carbonate, magnesiumhydroxide, calcium carbonate and calcium hydroxide, the remainder of thesteps being the same and the respective metal salt of1,1-dihydroxy-3,3'-dicarboxy 8,8digentiobiosyloxy-l0,l0'-dihydrodianthrone is obtained, namely: thesodium salt of l,1'-dihydroxy-3,3-dicarboxy 8,8'- digentiobiosyloxy-lO,l0-dihydrodianthrone; the potassium salt of 1,1-dihydroxy-3,3'-dicarboxy3,8'-digentiobiosylow-l0,10'-dihydrodianthrone; the lithium saltof1,l'-dihydroxy-3,3'rdicarboxy-8,8-digentiobiosyloxy-10,10-dihydrodianthrone; the magnesium salt of1,1'-dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-IO,10-dihydrodianthrone, and the calcium salt of1,1'-dihydroxy-3,3'-dicarboxy-8,8'-digentiobiosyloxy-IO,10'-dihydrodianthrone.

EXAMPLE 9 7 When the1,l-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-10,10-dihydrcdianthroneor its metal salts are utilized in the preparation of solutions, thevehicle may be either water, glycerin, propylene glycol, syrup ormixtures of these. The solutions are prepared by direct dissolution ofthe appropriate quantity ofthe active ingredient, in approximatelypercent of the final volume of the amount of solution to be prepared ofthe particular vehicle chosen. When all of the active ingredients havebeen added and dissolved in the vehicle, the solution is filtered andbrought to proper volume with additional amounts of vehicle. Aconvenient unitdosage range is 5 .cc. or 1 teaspoonful and theconcentration of active ingredient may be adjusted therein to be from 1'mg. to 40 mg. per unit dose. It may be desired to employ a from thegroup consisting of sodium, potassium, lithium, magnesium, calcium, and

(d) adding an anhydrous form of said organic solvent to precipitate awater-soluble product containing the metal salt of1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-IO,10-dihydrodianthroneand isolating said precipitate in the dry form.

10. The process of preparing1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy 10,10dihydrodianthrone Which comprises the steps of:

(a) dissolving in water the precipitated Water-soluble product obtainedas described in claim 9,

(b) treating the resultant aqueous solution with an agent selected fromthe group consisting of cationic ion exchange resin and acid ions whichprecipitate the metal ions present in said aqueous solution,

(c) separating the liquid phase,

(d) concentrating the liquid phase and adding an anhydrous form of anorganic solvent selected from the group consisting of ethanol, methanol,propanol, isopropanol, acetone, dioxane and mixtures of these, and

(e) isolating the formed 1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy 10,10 dihydrodianthrone therefrom.

11. The process of preparing a metal salt of l,l-dihydroxy-3,3-dicarboxy8,8 digentiobiosyloxy-IO,10- dihydrodianthrone Which comprises the stepsof dissolving 1,1-dihydroxy-3,3-dicarboxy 8,8digentiobiosyloxyl0,l-dihydrodianthrone in Water, adding a metalcompound selected from the group of metas consisting of sodiumbicarbonate, sodium carbonate, sodium hydroxide, potassium hydroxide,potassium carbonate, potassium bicarbonate, lithium carbonate, lithiumbicarbonate, lithium hydroxide, magnesium carbonate, magnesiumhydroxide, calcium carbonate and calcium hydroxide, adding an anhydrousorganic solvent from the group consisting of ethanol, methanol, andisopropanol, and isolating the formed metal salt of1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-lO,l0-dihydrodianthrone, namely the sodium salt ofl,l'-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-10,10-dihydrodianthrone,potassium salt of 1, 1-dihydr xy-3,3-dicarboxy 8,8 digentiohiosyloxy-lilO-dihydrodianthrone, lithium salt of 1,l-dihydroxy-3,3- dicarboxy 8,8digentiobiosyloxy 10,10 dihydrode anthrone; calcium'salt ofl,l-dihydroxy-3,3-dicarboxy-8,8'-digentiobiosyloxy-l0,10'-dihydrodianthrone and mag ncsium salt of1,1-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyloxy-IO,10'-dihydrodianthrone.

12. The process of preparing the calcium salt of 1,1- dihydroxy3,3-dicarboxy 8,8 digentiobiosyloxy-l0,10- dihydrodianthrone whichcomprises the steps of adding an ionizable calcium compound to asolution of 1,l'-dihydroxy-3,3'-dicarboxy 8,8 digentiobiosyioxy-ll),l0-dihydrodianthrone dissolved in a solvent selected from the groupconsisting of Water, methanol, ethanol, propanol, isopropanol, acetone,dioxane and mixtures of these and recovering the formed calcium salt of1,1'-dihydroxy- 3,3-dicarboxy-8,8'-digentiobiosyloxy 10,10dihydrodianthrone.

13. The process of preparing the magnesium salt of 1, l-dihydr0xy 3,3dicarboxy 8,8 digentiobiosyloxyl0,1G-dihydrodianthrone Which comprisesthe steps of adding an ionizable magnesium compound to a solution of1,1-dihydroxy 3,3 dicarboxy-S,8-digentiobiosyloxy-10,10-dihydrodianthrone dissolved in a solvent selected from the grouconsisting of Water, methanol, ethanol, propanol, isopropanol, acetone,dioxane and mixtures of these and recovering the formed magnesium saltof 1,1- dihydroxy-3,3-dicarboxy 8,8 digentiobiosyloxy-IO,l0'-dihydrodianthrone.

14. The method of achieving a laxative efiect in a mammal whichcomprises the steps of introducing into the alimentary tract of saidmammal a preparation includin a pharmaceutical carrier and from 1 to 40mg. of a compound selected from the group consisting of1,l'-dihydroxy-3,3-dicarboxy 8,8 digentiobiosyloxy-l0,10-dihydrodianthrone and its pharmaceutically acceptable metal salts.

15. The method of achievin a laxative efiiect in a mammal whichcomprises the steps of introducing into the alimentary tract of saidmammal a preparation including a pharmaceutical carrier and from 1 to 40mg. of 1,1- dihydroxy-3,3-dicarboxy 8,8 digentiobiosyloxy-IO,10-dihydrodianthrone.

16. The method of achieving a laxative effect in a mammal whichcomprises the steps of introducing into the alimentary tract of saidmammal a preparation includ ing a pharmaceutical carrier and from 1 to40 mg. of a compound selected from the group consisting of the sodiumsalt of 1,l'-dihydr0xy-3,3-dicarboxy 8,8digentiobiosyloxy-10,10'-dihydrodianthrone, magnesium salt ofl,1-dihydroxy-3,3'-dicarboxy 8,8 digentiobiosyloxy-10,l0-dihydrodianthrone, lithium salt of 1,l-dihydroxy-3,3-dicarboxy-8,8-digentiobiosyl0xy 10,10 dihydrodianthrone, potassiumsalt of 1,l-dihydroxy-3,3-dicarboxy- 8,8digentiobiosyloxy-IO,l0-dihydrodianthrone, calcium salt of1,1-dihydroxy-3,3-dicarboxy-8,8-digenti0biosyloxy-IO,10-dihydrodianthroneand mixtures of these.

References Cited Fairbairn et al.: J. Pharmacy and PharmacoL, vol. 3,No. 12, December 1951, pages 918-925.

SAM ROSEN, Primary Examiner.

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 1,1'' -DIHYDROXY-3,3''-DICARBOXY-8,8''-DIGENTIOBIOSYLOXY-10,10''-DIHYDRODIANTHRONE AND ITS PHARMACEUTICALLY ACCEPTABLE METAL SALTS.14. THE METHOD OF ACHIEVING A LAXATIVE EFFECT IN A MAMMAL WHICHCOMPRISES THE STEPS OF INTRODUCING INTO THE ALIMENTARY TRACT OF SAIDMAMMAL A PREPARATION INCLUDING A PHARMACEUTICAL CARRIER AND FROM 1 TO 40MG. OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF1,1''-DIHYDROXY-3,3''-DICARBOXY - 8,8'' -DIGENTIOBIOSYLOXY-10,10''DIHYDRODIANTHRONE AND ITS PHARMACEUTICALLYACCEPTABLE METAL SALTS.